This invention relates to conditioning arrangements for conditioning a liquid circulated through a system, and in particular to regulating the temperature of the liquid.
Liquid may typically be circulated through a system to provide motive power to one or more elements of the system or to provide lubrication to bearings of an engine or the like.
Considering an engine lubrication system, a lubricating liquid such as, oil, is circulated by way of a pump driven by the engine and passed through a conditioning arrangement which conditions the liquid by cleaning the liquid of solid contaminants.
It is known to provide such a conditioning arrangement with both so-called full flow cleaning elements and by-pass centrifugal cleaning elements.
Examples of such arrangements containing both cleaning element types are disclosed in GB-A-2160796, GB-A-2160449 and DE-C1-4306431, all of which disclose coaxially arranged full flow and centrifugal cleaning elements within housing means that is arranged to be coupled to an engine block. The housing means forms part of a liquid lubricant circulation system of the engine, receiving a liquid lubricant therefrom and returning it thereto by way of aligned passages or ducts. Most of the liquid, after passage through the full flow element, is returned to the engine under pressure in order to lubricate bearings etc. whereas a proportion of the lubricant by-passes that element to the centrifugal cleaning element from which it is returned directly to a reservoir or sump.
GB-A-2160449 discloses coaxially disposed cleaning elements, one surrounding the other, and capable of separate removal in an axial direction, whereas GB-A-2160796 discloses cleaning elements axially displaced and accessible from different axial directions by way of separately removable parts of the housing means. DE-C1-4306431 discloses both cleaning elements axially displaced within a single housing and removable in the same axial direction.
While the presence of both cleaning element types in a conditioning arrangement serves to condition the liquid in an efficient manner by removing contaminant particles of all sizes, cleaning the liquid of solid contaminants does not necessarily place the liquid in optimum condition if the operating conditions are such that the liquid is too cold to flow properly or so hot that its viscosity falls.
It is of course known to have sump heating means to raise the temperature of liquid lubricant at start-up in extremely cold climates, notwithstanding that in an internal combustion engine, the temperature is soon raised to an operating norm.
It is known also to have heating and/or cooling means associated with lubricating liquid for use by an engine as it is circulated and cleaned by a typical full flow cleaning element.
Such means may take the form of a heat exchanger matrix disposed separately of the engine block, usually where it is in a stream of cooler air caused to pass across it, and liquid is piped from the engine thereto and back again. Such a matrix may have a full flow filter in line with the liquid flow, but the use of a discrete matrix and external pipework increase both initial and maintenance costs, assuming space is available, while also being potentially vulnerable to damage. The damage that can be caused by loss of liquid lubricant, even at a small rate in a relatively short interval (compared with the wide tolerance of viscosity changes acceptable to most engines,) means that temperature regulation of the liquid by such externally effected lubricant cooling is employed only where it is considered essential and, not merely beneficial to engine efficiency.
As an alternative to such remote cooling of liquid lubricant, engines which have the liquid cleaned by a full flow cleaning element of the self-contained kind, that is, as a sealed canister containing a paper, or like, filter element and adapted to be screwed onto a mounting block which also transfers liquid to and from the engine, may have the mounting block adapted to include or support a simple heat exchanger element in the form of a water jacket to which the canister is actually screwed and through which the liquid is directed by additional pipework or ducting.
Examples of liquid lubricant cleaning arrangements which have such associated heat exchanger elements are disclosed in GB-A-2163967, EP-A-0200809, DE-C-3444267 and DE-A-1934193.
If the mounting is adapted such that the heat exchanger is formed integrally within it, the casting becomes complex, whereas if it is a separate element interposed between conventional mounting block and the cleaning element canister, there are two interfaces for liquid transfer that have potential for leakage.
Such arrangements as described also introduce resistance into the liquid flow by forcing it through a confined passage of the heat exchanger and do not offer a cost effective approach to effecting such cooling, or possibly heating, of liquid when the cleaning includes not only a full flow cleaning element but also a selfWO powered centrifugal cleaner to operate on a portion of the liquid by-passing the full flow cleaning element.
It will be appreciated that liquid cleaning and conditioning systems are not restricted only to lubricating oil systems of internal combustion engines, and preserving the generality of the foregoing it is an object of the present invention to provide a liquid temperature regulating liquid conditioning arrangement which includes liquid filtering by both full flow and centrifugal cleaning elements that is of simple, compact and practicable construction, and which mitigates actual or potential disadvantages of techniques hitherto previously adapted to perform a similar function.
According to the present invention a temperature regulating liquid conditioning arrangement comprises housing means, adapted for attachment to apparatus for supplying liquid under pressure and utilizing conditioned liquid returned thereto, having defined therein a plurality of chambers arranged individually to contain centrifugal and full flow cleaning elements disposed coaxially with respect to each other and with respect to a single housing closure means providing access to the housing chambers, and heat exchange means comprising a heat exchange element operably disposed within a chamber of the housing filled with the liquid and in the liquid flow path of the full flow cleaning element such that the liquid is exposed to the heat exchange element.